Problem: What is the least common multiple of 18 and 30? Another way to say this is: $\lcm(18, 30) = {?}$
Explanation: The least common multiple is the smallest number that is a multiple of 18 and 30. We know that 18 x 30 (or 540) is a common multiple, but is it the least common multiple? Write out the multiples of 30 until we find a number divisible by 18. 30, 60, 90, So, 90 is the least common multiple of 18 and 30.